Invasive Non-Native Plants in Invasive Non-Native Plants in the Lower Elwha Watershedthe Lower Elwha Watershed

Elwha Ecosystem RestorationPreparing for the Revegetation of the Reservoirs

Olympic National ParkIn partnership with

The Lower Elwha Klallam Tribe

Lower Elwha Klallam ReservationLower Elwha Klallam Reservation

Glines Canyon DamGlines Canyon Dam

Strait of Juan De Fuca

Olympic National

Park

Highway 112

Highway 101

Port Angeles

Robyn Hill

Geyser ValleyGeyser Valley

Elwha DamElwha Dam

Lower Elwha Klallam ReservationLower Elwha Klallam Reservation

Glines Canyon DamGlines Canyon Dam

Strait of Juan De Fuca

Olympic National

Park

Highway 112

Highway 101

Port Angeles

Robyn Hill

Geyser ValleyGeyser Valley

Elwha DamElwha Dam

EXPECTED CONDITIONSCritical Ecosystem processes will be severely damaged (erosion, nutrient cycling, hydrology)

Natural succession of the middle areas of the reservoirs expected to be slow

Lake Aldwell Lake MillsGlines Canyon DamGlines Canyon Dam

Elwha DamElwha Dam

Managing Invasive Species in the Managing Invasive Species in the Lower ElwhaLower Elwha

• Prioritize species to manage– From 1991-2008, 147 exotic species have

been observed in the lower Elwha watershed– Rank species according to invasive potential

• Resources: – County and State noxious weed lists– NatureServe.org– Park data– Scientific literature

The Top “Species of Concern” The Top “Species of Concern” known to occur in the Lower Elwhaknown to occur in the Lower Elwha

Species Common Name

Bromus tectorum cheatgrass

Centaurea biebersteinii spotted knapweed

Centaurea debeauxii ssp. thuillieri meadow knapweed

Centaurea diffusa diffuse knapweed

Centaurea jacea brown knapweed

Cirsium arvense Canadian thistle

Cytisus scoparius Scot's broom

Geranium robertianum herb Robert

Hedera helix English Ivy

Hypericum perforatum common St. John's wort

Ilex aquifolium English holly

Lathyrus latifolius perennial pea

Species Common Name

Lathyrus sylvestris small everlasting peavine

Linaria vulgaris butter and eggs

Phalaris arundinacea reed canarygrass

Polygonum cuspidatum Japanese knotweed

Polygonum sachalinense giant knotweed

Polygonum x bohemicum Bohemian knotweed

Potentilla recta sulfur cinquefoil

Prunus laurocerasus Laurel cherry

Rubus discolor Himalayan blackberry

Rubus laciniatus evergreen blackberry

Senecio jacobaea tansy ragwort

Bromus tectorum (cheatgrass)

• Annual grass• Cheatgrass mainly

threatens dry, grassland ecosystems– May be common in riparian

communities

• Can drastically change fire regime

• Depletes soil moisture early in growing season

Spikelets 15-20mmSpikelets 15-20mm

Pubescent blades and sheathsPubescent blades and sheaths

Cytisus scoparius (Scot’s broom)

• Evergreen, perennial shrub

• Aggressive invader currently infesting over 2 million acres in CA, WA, and OR

• Alters soil nutrient regime by adding nitrogen

• Creates monocultures• Can change fire regimes

Geranium robertianum (herb Robert, stinky Bob)

• Semi-evergreen, semi-perennial forb

• Aggressive invader of shady forests and sunny sites

• Creates monocultures• Seeds prolifically• Seed dispersed by

ejecting out of pods and sticking to travelers

Phalaris arundinacea (reed canarygrass)

• Perennial, rhizotomous grass

• Forms dense single species stands– Inhibits native– Reduces diveristy

• Little value to wildlife• Alters hydrology in

streams, wetlands

Ligules: membranous 4-10 mmLigules: membranous 4-10 mm

Polygonum spp. (the BIG knotweeds)

• Includes P. sachalinense, P. cuspidatum, and P. x bohemicum

• Displaces streamside vegetation

• Causes increased bank erosion and clogs small waterways

• Forms thickets up to 12 feet tall and produces allelochemicals

• Spreads mainly by rhizomes but also by fragments of root

Rubus armeniacus (Himalayan blackberry)

• Displaces streamside and upland vegetation

• Forms thickets up to 12 feet tall

• Vegetatively spreads by rhizomes and by fragments of root

• Birds and mammals disperse the seed

Managing Invasive Species in the Managing Invasive Species in the Lower ElwhaLower Elwha

• Prioritize species to manage– Locate populations of the primary species of

concern in the Elwha watershed• 2001 mapping project

Roads

ONP Trails

Reveg Project Boundary

2001 Survey Points

Roads

ONP Trails

Reveg Project Boundary

2001 Survey Points

2008 Survey Points

Managing Invasive Species in the Managing Invasive Species in the Lower ElwhaLower Elwha

• Treat priority species in watershed prior to dam removal

• Prioritize sites to manage– Areas directly adjacent to reservoirs– Areas we will use as staging sites for

revegetation activities– Use model of propagule movements to

identify invasive population “hot spots”

Managing Invasive Species in the Managing Invasive Species in the Lower ElwhaLower Elwha

• Treatments– Herbicides specific for each species/situation– Hand-pull some species

• Scot’s broom• Herb Robert• Young seedlings of English holly